Isotope detection methods

Abstract

The present invention provides an isotope detection method, specifically: after being ionized, the isotope enters a multipolar rod mass analyzer, and the mass range of the element corresponding to the isotope is screened; the screened ions enter a time-of-flight mass analyzer, and when the last ion that entered the time-of-flight mass analyzer has not yet reached the detector, the next ion enters the time-of-flight mass analyzer. The present invention has the advantages of high analysis accuracy.

Description

Technical Field

[0001] The present invention relates to element analysis, and in particular to an isotope detection method. Background Art

[0002] Isotopes refer to elements with the same atomic number (number of protons) but different mass numbers (number of neutrons). They can be divided into stable isotopes and radioactive isotopes. Stable isotopes are a type of naturally occurring isotopes that cannot be detected by technical means for radioactivity. In practice, the content of stable isotopes in nature is relatively low, and it is difficult to express the difference between isotopes in absolute terms. Therefore, the relative measurement method is used in practice, that is, the isotope ratio of the sample is obtained based on the isotope ratio of the measured sample and the isotope ratio of the corresponding standard. Stable isotopes are widely used in soil, medicine, agriculture, biology, ecology, environment and other fields.

[0003] In many applications, the accuracy of isotope ratio determination is very high. The isotope accuracy ratio of traditional quadrupole mass spectrometers can only reach 0.2%, which cannot meet the application requirements of isotope ratios in various fields. At this time, magnetic mass spectrometry is needed to achieve high-precision isotope determination. Magnetic mass spectrometry separates elements through dual focusing of magnetic field and electric field, and detects multiple isotopes simultaneously through multiple channel detectors, so that different isotope channels can be measured at the same time at any time, and the fluctuation errors of samples, injections and plasma can be completely eliminated, so as to achieve high isotope measurement accuracy. However, magnetic mass spectrometry requires a huge magnetic field and extremely high vacuum requirements, the cost is high, and it is difficult to operate and maintain. It is difficult to be promoted in all fields and is limited to scientific research purposes. Summary of the invention

[0004] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides an isotope detection method.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] Isotope detection method, the isotope detection method is:

[0007] After being ionized, the isotopes enter the multi-stage mass analyzer to screen the mass range of the element corresponding to the isotope;

[0008] The screened ions enter the time-of-flight mass analyzer, and the next ion enters the time-of-flight mass analyzer before the last ion flying in the time-of-flight mass analyzer reaches the detector; the time difference Δt between adjacent times satisfies:

[0009] D is the length of the flight cavity in the time-of-flight mass analyzer, e is the unit charge, E is the electric field strength in the flight cavity, Z is the total charge number, m1 is the maximum isotope number of the selected element, and m2 is the minimum isotope number of the selected element.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. High detection accuracy;

[0012] The time-of-flight mass analyzer works in a vertical introduction mode, which reduces energy dispersion;

[0013] All ions entering the time-of-flight mass analyzer are generated at the same time, thus avoiding sample fluctuations caused by system injection and electrical signal fluctuation noise, greatly improving the analysis accuracy of ions;

[0014] At the same time, since the ions entering the time-of-flight mass analyzer contain only very small fragments of ions, the mass range deviation generally does not exceed 5, so the time of the ions in the flight chamber can be fully utilized. In one cycle of ion flight, the repeated pulse method can be used to increase the reuse rate of ions, increase the average number of calculations, and improve the accuracy of analysis;

[0015] During debugging, the spatial positions of the vertical torch and coil are precisely and synchronously adjusted to achieve the best position under each working condition and obtain the most accurate detection data;

[0016] The torch can be fine-tuned in three dimensions, with position accuracy and repeatability up to 0.01mm in three directions, achieving the best position between the torch flame and the cone.

[0017] The time-of-flight mass spectrometer of the present invention can achieve second-order time focusing for wider ion initial position dispersion, and the mass resolution is significantly improved;

[0018] 2. High sensitivity;

[0019] The use of double pulse repulsion technology can reduce the technical requirements for high voltage pulses; the patent of this invention adopts a double repulsion method of positive pulse push (repulsion electrode) and negative pulse pull (traction electrode), which can reduce the demand for high voltage by half, so the rising edge is steeper and the pulse waveform can be improved;

[0020] Adding the first grid and the second grid of equal potential in the middle of the double pulse repulsion can reduce the electric field penetration effect of the acceleration region on the ion modulation region;

[0021] The first grid and the second grid are directly grounded, without adding extra voltage, and the adjustment is easy;

[0022] It can achieve a wider modulation area and improve ion flux and sensitivity;

[0023] 3. Good reliability;

[0024] The torch is set vertically and remains relatively still with the coil. The torch and the coil move synchronously to prevent the torch from getting too close to the coil and burning the torch, thus solving the problem of deformation of the sampling cone.

[0025] The conversion module and the conversion member are used to reliably convert the rotation of the motor into the vertical movement of the conversion member. The use of multiple guide members allows the support member and the conversion member to move only in the vertical direction, effectively preventing the support member from tilting and ensuring the accuracy and reliability of the torch positioning.

[0026] 4. Low cost and good maintainability;

[0027] Inductively coupled plasma mass spectrometer, multi-pole mass analyzer and time-of-flight mass analyzer are all mature technologies with low cost and good maintainability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings:

[0029] Figure 1 is a flow chart of an isotope detection method according to an embodiment of the present invention;

[0030] Figure 2 is a schematic structural diagram of a mass spectrometer according to an embodiment of the present invention;

[0031] Figure 3 is a schematic structural diagram of a bearing unit according to an embodiment of the present invention;

[0032] Figure 4 is a schematic structural diagram of a time-of-flight mass analyzer according to an embodiment of the present invention;

[0033] Figure 5 is a schematic structural diagram of a time-of-flight mass analyzer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] Figure 1-5The following description describes the optional embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to explain the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or replacements derived from these embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional embodiments, but is only limited by the claims and their equivalents.

[0035] Embodiment 1:

[0036] Figure 1 A flow chart of the isotope detection method according to an embodiment of the present invention is given. Figure 1 As shown, the isotope detection method is:

[0037] After being ionized, the isotopes enter the multi-stage mass analyzer to screen the mass range of the element corresponding to the isotope;

[0038] The screened ions enter the time-of-flight mass analyzer, and the next ion enters the time-of-flight mass analyzer before the last ion flying in the time-of-flight mass analyzer reaches the detector; the time difference Δt between adjacent times satisfies:

[0039] D is the length of the flight cavity in the time-of-flight mass analyzer, e is the unit charge, E is the electric field strength in the flight cavity, Z is the total charge number, m1 is the maximum isotope number of the selected element, and m2 is the minimum isotope number of the selected element.

[0040] In order to improve the detection accuracy, further, in the mass spectrometry detection, a time-of-flight mass analyzer is used, the time-of-flight mass analyzer includes a repeller, a field-free flight zone and a detector, the field-free flight zone includes a first incident grid; the time-of-flight mass analyzer also includes:

[0041] A pull electrode, wherein a first ion acceleration region is formed between the pull electrode and the first incident grid;

[0042] A first grid and a second grid, wherein the potential difference between the first grid and the second grid is zero; a second ion acceleration zone is formed between the repeller and the first grid, and between the second grid and the traction electrode; ions sequentially pass through the first grid, the second grid, the traction electrode, the first incident grid and the field-free flight zone, and are received by the detector.

[0043] The time-of-flight mass analyzer further comprises:

[0044] The reflection zone includes a first reflection field and a second reflection field, the first reflection field includes a second incident grid and a reflection electrode, and the second reflection field includes the reflection electrode and a reflection plate; ions emitted from the field-free flight zone are reflected by the reflection zone and then received by the detector.

[0045] In order to achieve second-order focusing, the second ion acceleration region and the first reflection field and the second reflection field satisfy:

[0046]

[0047]

[0048] E1, E3, E4, and E5 are the electric field intensities of the second ion acceleration region, the first ion acceleration region, the first reflection field, and the second reflection field, respectively. G d2, d3, d4, and d5 are respectively the distance between the incident ion and the first grid, the distance between the first grid and the second grid, the distance between the second grid and the traction electrode, the distance between the traction electrode and the first incident grid, the distance between the second incident grid and the reflection electrode, and the distance between the reflection electrode and the reflection plate; L is the length of the ion flying between the first incident grid and the detector.

[0049] In order to achieve second-order focusing, the second ion acceleration region and the field-free reflection region satisfy:

[0050]

[0051]

[0052] E1 and E3 are the electric field strengths of the second ion acceleration region and the first ion acceleration region, respectively. G d1, d2, and d3 are respectively the distance between the incident ion and the first grid, the distance between the first grid and the second grid, the distance between the second grid and the traction electrode, and the distance between the traction electrode and the first incident grid; L is the length of the ion flying between the first incident grid and the detector.

[0053] In order to reduce energy dispersion, further, in the time-of-flight mass analyzer, from top to bottom, ions pass through the first grid, the second grid, the first incident grid and the field-free flight zone in sequence.

[0054] In order to improve operational reliability, after the isotopes are ionized, the ions move vertically upward.

[0055] In order to improve the detection accuracy, further, in mass spectrometry detection, the specific method of ionization is:

[0056] The motor rotates, and the conversion module converts the rotation of the motor into linear movement of the sliding member;

[0057] The linear movement of the sliding member is converted into the vertical movement of the conversion member, thereby driving the carrier connected to the conversion member to move vertically along a plurality of guide members, and the carrier unit arranged on the carrier moves vertically along with the carrier; the torch tube is vertically arranged on the carrier unit, and the coil is fixed on the carrier unit and remains relatively still with the torch tube;

[0058] Two-dimensionally adjusting the position of the bearing unit in the horizontal direction, the bearing unit is arranged on a two-dimensional adjustment unit, and the two-dimensional adjustment unit is arranged on the bearing member;

[0059] The sample enters the torch tube and is excited into plasma by the coil, thereby forming ions;

[0060] The ions pass through the sampling cone and enter the mass spectrometry unit.

[0061] In order to improve the detection accuracy, the ions directed vertically upward are further deflected and then enter a horizontally arranged multi-pole mass analyzer.

[0062] In order to improve the detection accuracy, further, when the ions that last entered the time-of-flight mass analyzer have not yet reached the detector, multiple ions enter the time-of-flight mass analyzer.

[0063] Embodiment 2:

[0064] An example of application of the isotope detection method according to Example 1 of the present invention in uranium isotope detection.

[0065] In this application example, the uranium isotopes are:

[0066]

[0067]

[0068] There are stable isotopes U234, U235, and U238 in nature. When analyzing and measuring, we are not only concerned with the total amount of U isotopes, but also the abundance of isotopes, which is extremely valuable for energy development, material application, and safety monitoring. The traditional quadrupole mass spectrometer is not accurate enough for isotope analysis, and the double-focusing magnetic mass spectrometer for traditional isotope analysis is extremely expensive, which is costly to use in conventional analysis fields.

[0069] In this embodiment, ICP-TOF-MS is used to achieve ionization and analysis, and the multi-pole mass analyzer adopts a quadrupole mass analyzer. The specific structure of ICP-TOF-MS is as follows:

[0070] like Figure 2As shown, the torch tube 101 and the coil 102 are respectively arranged on different components of the carrying unit, and the torch tube 101 and the coil 102 remain relatively stationary;

[0071] like Figure 3 As shown, the bearing unit includes a fixing portion 301, a first mounting portion 302, a second mounting portion 303 and a connecting portion 304; the second mounting portion 303 is horizontally fixed on the first adjusting unit 201, the fixing portion 301 is fixed on the upper side of the second mounting portion 303, the connecting portion 304 is vertically arranged, the lower end is fixed on the second mounting portion 303, and the upper end is fixed to the horizontally arranged first mounting portion 302; the torch tube 101 is vertically arranged on the first mounting portion 302, one end of the coil 102 is fixed on the fixing portion 301, and the other end surrounds the torch tube 101;

[0072] like Figure 2 As shown, the second adjustment unit is fixed on the chassis 100, and includes a motor 401, a screw 402, a nut 403, a guide rail 404, a sliding member 405 and a bearing. The motor 401 drives the horizontally arranged screw 402 to rotate, the nut 403 is sleeved on the screw 402 by a thread, the sliding member 405 is arranged on the guide rail 404 arranged parallel to the screw 402, and the nut 403 is connected to the sliding member 405, so that when the unit screw 402 rotates, the sliding member 405 is driven to move horizontally and linearly along the guide rail 404; the bearing is arranged at the top of the sliding member 405; The four corners of the bearing member 503 are respectively provided with through holes for allowing the vertically arranged guide member 504 to pass through, and the inner diameter of the through hole is slightly different from the outer diameter of the guide member 504, so that the bearing member 503 can only move vertically along the guide member 504; the conversion member has a vertical portion 501 and an inclined portion 502, the lower end of the vertical portion 501 is connected to the bearing member 503, and the upper end is connected to the inclined portion 502, the inclined portion 502 is supported by the bearing, and the sliding member 405 moves horizontally and linearly at the lower side of the inclined portion 502, so that the inclined portion 502 can only move vertically;

[0073] The first adjustment unit 201 uses an electric two-dimensional mobile platform to achieve two-dimensional adjustment in the horizontal direction, and is arranged on the carrier 503;

[0074] The specific method of ionization is:

[0075] The motor rotates, and the driving nut 403 carries the sliding member 405 to move horizontally and linearly on the guide rail 404;

[0076] The sliding member 405 moves horizontally and linearly below the inclined portion 502 of the conversion member, thereby converting the conversion member into vertical movement (the conversion member only moves vertically), thereby driving the support member 503 connected to the conversion member to move vertically along a plurality of guide members 504 (the support member 503 only moves vertically), and the support unit arranged on the support member 503 moves vertically along with the support member 503; the torch tube 101 is vertically arranged on the first mounting portion 302 of the support unit, and the coil 102 is fixed on the fixing portion 301 of the support unit and remains relatively still with the torch tube 101;

[0077] The first adjusting unit 201 is used to adjust the position of the carrier unit in two dimensions in the horizontal direction. The carrier unit is arranged on the first adjusting unit 201, and the first adjusting unit 201 is arranged on the carrier 503. It can be seen that during the three-dimensional adjustment of the carrier unit, the torch tube 101 and the coil 102 remain relatively still.

[0078] When the sample enters the torch tube 101, it is excited into plasma by the coil 102, thereby forming ions;

[0079] The ions move vertically upward, pass through the sampling cone 103, enter the ion deflection module, and then enter the quadrupole mass analyzer horizontally;

[0080] Figure 4 A schematic diagram of the structure of a time-of-flight mass analyzer according to an embodiment of the present invention is given. Figure 4 As shown, the time-of-flight mass analyzer comprises:

[0081] A repeller 11, a field-free flight zone 30 and a detector 51, wherein the field-free flight zone 30 includes a first incident grid 31;

[0082] A traction electrode 12, wherein a first ion acceleration region is formed between the traction electrode 12 and the first incident grid 31;

[0083] a first grid 21 and a second grid 22, wherein the potential difference between the first grid 21 and the second grid 22 is zero; a second ion acceleration region is formed between the repeller 11 and the first grid 21, and between the second grid 22 and the pull electrode 12; ions sequentially pass through the first grid 21, the second grid 22, the pull electrode 12, the first incident grid 31 and the field-free flight region 30, and are received by the detector 51; the first grid 21 and the second grid 22 are grounded, thereby ensuring that the first grid 21 and the second grid 22 have equal potentials;

[0084] There are multiple electrodes between the pull electrode 12 and the first incident grid 31 that allow ions to pass through, and the multiple electrodes are divided by a voltage divider resistor; there are multiple electrodes between the pull electrode 12 and the first incident grid 31 that allow ions to pass through, and the multiple electrodes are divided by a voltage divider resistor, so that the electric field intensity of the first ion acceleration zone is uniform; the power supply applies a positive pulse voltage to the repeller 11 and a negative pulse voltage to the pull electrode 12; the second ion acceleration zone and the field-free reflection zone meet the following conditions:

[0085]

[0086]

[0087] E1 and E3 are the electric field strengths of the second ion acceleration region and the first ion acceleration region, respectively. G d1, d2, and d3 are respectively the distance between the incident ion and the first grid 21, the distance between the first grid 21 and the second grid 22, the distance between the second grid 21 and the traction electrode 12, and the distance between the traction electrode 12 and the first incident grid 31; L is the length of the ion flying between the first incident grid 31 and the detector 51.

[0088] Ions from the quadrupole mass analyzer enter the time-of-flight mass analyzer. When flying in the time-of-flight mass analyzer, the ions pass through the first grid, the second grid, the traction electrode 12, the first incident grid and the field-free flight zone from top to bottom, that is, the ions enter the time-of-flight mass analyzer vertically.

[0089] In this embodiment, U element is taken as an example. When the quadrupole scans, it does not work with unit mass scanning. By setting the scanning parameters, the quadrupole scans so as to cover the range from 234 to 238, so that all U elements can enter the time-of-flight mass analyzer through the quadrupole scan.

[0090] The time-of-flight mass analyzer works in a vertical introduction mode, which reduces energy dispersion;

[0091] The ions entering the time-of-flight mass analyzer only contain the element information in the mass range of 234 to 238. After the ions drift through the flight time, they are separated due to the difference in speed. All ions entering the time-of-flight mass analyzer are generated at the same time, so the sample fluctuation caused by the system injection and the fluctuation noise of the electrical signal can be avoided, greatly improving the analysis accuracy of the ions.

[0092] At the same time, since the ions entering the time-of-flight mass analyzer contain only very small fragments of ions, the mass range deviation generally does not exceed 5. Therefore, the time of the ions in the flight chamber can be fully utilized. During one cycle of ion flight, repeated pulses can be used to increase the reuse rate of ions, increase the average number of calculations, and improve the accuracy of analysis.

[0093] Embodiment 3:

[0094] An application example of the isotope detection method according to Example 1 of the present invention.

[0095] In a time-of-flight mass analyzer, e.g. Figure 5 As shown, the first grid 21 and the second grid 22 are grounded, ensuring that the first grid 21 and the second grid 22 have equal electric potential; there are multiple electrodes between the traction electrode 12 and the first incident grid 31 that allow ions to pass through, and the multiple electrodes are divided by a voltage dividing resistor to make the electric field strength of the first ion acceleration zone uniform; the power supply applies a positive pulse voltage to the repeller 11 and a negative pulse voltage to the traction electrode 12;

[0096] The reflection area includes a first reflection field and a second reflection field, the first reflection field includes a second incident grid 32 and a reflection electrode 41, and the second reflection field includes the reflection electrode 41 and a reflection plate 42; ions emitted from the field-free flight area 30 are reflected by the reflection area and then received by the detector 51;

[0097] In the first ion acceleration region and the first reflection field and the second reflection field, multiple electrodes that allow ions to pass through are arranged, and the multiple electrodes are divided by voltage-dividing resistors to make the electric field strength in the first ion acceleration region, the first reflection field and the second reflection field uniform;

[0098] The second ion acceleration region and the first reflection field and the second reflection field satisfy:

[0099]

[0100]

[0101] E1, E3, E4, and E5 are the electric field intensities of the second ion acceleration region, the first ion acceleration region, the first reflection field, and the second reflection field, respectively. G d2, d3, d4, and d5 are respectively the distance between the incident ion and the first grid 21, the distance between the first grid 21 and the second grid 22, the distance between the second grid 22 and the traction electrode 12, the distance between the traction electrode 12 and the first incident grid 31, the distance between the second incident grid 32 and the reflection electrode 41, and the distance between the reflection electrode 41 and the reflection plate 42; L is the length of the ion flying between the first incident grid 31 and the detector 51.

[0102] In ICP, the difference from Example 2 is:

[0103] 1. The second mounting portion and the connecting portion are no longer provided, the fixing portion is directly fixed on the first adjusting unit, and the first mounting portion is horizontally fixed on the fixing portion;

[0104] 2. The screw and the guide rail should be kept parallel and inclined relative to the horizontal plane;

[0105] 3. The conversion member includes a horizontal part and a vertical part, and the horizontal part is supported by a sliding member; when the sliding member that moves in an inclined linear manner moves under the horizontal part of the conversion member, the conversion member moves vertically therewith, and only moves vertically.

Claims

1. Isotope detection method, the isotope detection method is: After being ionized, the isotopes enter the multipole mass analyzer to screen the mass range of the element corresponding to the isotope; The screened ions are all ions generated at the same time. These ions enter the time-of-flight mass analyzer. When the last ion that flew in the time-of-flight mass analyzer has not yet reached the detector, the next ion enters the time-of-flight mass analyzer; the time difference Δt between adjacent times satisfies: , D is the flight cavity length in the time-of-flight mass analyzer, e is the unit charge, E is the electric field strength in the flight cavity, Z is the total charge number, m1 is the maximum isotope number of the selected element, and m2 is the minimum isotope number of the selected element; The time-of-flight mass analyzer comprises a repeller, a field-free flight zone and a detector, wherein the field-free flight zone comprises a first incident grid; the time-of-flight mass analyzer further comprises: A pull electrode, wherein a first ion acceleration region is formed between the pull electrode and the first incident grid; a first grid and a second grid, wherein the potential difference between the first grid and the second grid is zero; a second ion acceleration region is formed between the repeller and the first grid, and between the second grid and the pull electrode; ions sequentially pass through the first grid, the second grid, the pull electrode, the first incident grid and the field-free flight region, and are received by the detector; a reflection region, the reflection region comprising a first reflection field and a second reflection field, the first reflection field comprising a second incident grid and a reflection electrode, the second reflection field comprising the reflection electrode and a reflection plate; ions emitted from the field-free flight region are reflected by the reflection region and then received by the detector; The second ion acceleration region and the first reflection field and the second reflection field satisfy: ； ； E1, E3, E4, and E5 are the electric field intensities of the second ion acceleration region, the first ion acceleration region, the first reflection field, and the second reflection field, respectively. G , d2, d3, d4, d5 are respectively the distance between the incident ion and the first grid, the distance between the first grid and the second grid, the distance between the second grid and the traction electrode, the distance between the traction electrode and the first incident grid, the distance between the second incident grid and the reflection electrode, and the distance between the reflection electrode and the reflection plate; L is the length of the ion flying between the first incident grid and the detector; The specific method of ionization is: The motor rotates, and the conversion module converts the rotation of the motor into a linear movement of a sliding member, wherein the sliding member is arranged on the guide rail; The linear movement of the sliding member is converted into the vertical movement of the conversion member, thereby driving the carrier connected to the conversion member to move vertically along a plurality of guide members, and the carrier unit arranged on the carrier moves vertically with the carrier; the torch tube is vertically arranged on the carrier unit, and the coil is fixed on the carrier unit and remains relatively still with the torch tube; the conversion member has a vertical part and an inclined part, the lower end of the vertical part is connected to the carrier, and the upper end is connected to the inclined part, the inclined part is supported by a bearing, and the bearing is arranged at the top end of the sliding member, and the sliding member moves horizontally and linearly at the lower side of the inclined part, so that the inclined part only moves vertically; Two-dimensionally adjusting the position of the bearing unit in the horizontal direction, the bearing unit is arranged on a two-dimensional adjustment unit, and the two-dimensional adjustment unit is arranged on the bearing member; The sample enters the torch tube and is excited into plasma by the coil, thereby forming ions; The ions pass through the sampling cone and enter the multipole mass analyzer.

2. The isotope detection method according to claim 1, characterized in that: The second ion acceleration region and the field-free reflection region satisfy: ； ； E1 and E3 are the electric field strengths of the second ion acceleration region and the first ion acceleration region, respectively. G d1, d2, and d3 are respectively the distance between the incident ion and the first grid, the distance between the first grid and the second grid, the distance between the second grid and the traction electrode, and the distance between the traction electrode and the first incident grid; L is the length of the ion flying between the first incident grid and the detector.

3. The isotope detection method according to claim 1, characterized in that: In a time-of-flight mass analyzer, from top to bottom, ions pass through the first grid, the second grid, the first incident grid and the field-free flight region in sequence.

4. The isotope detection method according to claim 1, characterized in that: After the isotope is ionized, the ions move vertically upward.

5. The isotope detection method according to claim 1, characterized in that: The vertically upward ions are deflected and enter the horizontally arranged multipole mass analyzer.

6. The isotope detection method according to claim 3, characterized in that: When the last ion that flew in the time-of-flight mass analyzer has not yet reached the detector, a plurality of ions enter the time-of-flight mass analyzer.

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